BACKGROUND.The double‐strand break (DSB) repair capacity has been implicated in the survival of patients in several cancer types. However, little is known about the prognostic importance of the key DSB repair genes—ataxia‐telangiectasia mutated (ATM), DNA‐dependent protein kinase catalytic subunit (DNA‐PKcs), and the Ku heterodimeric regulatory complex 86‐kD subunit (Ku80)—in nonsmall cell lung cancer (NSCLC). To address this issue, the authors determined the messenger RNA (mRNA) expression of these genes in patients NSCLC and assessed their prognostic relevance.METHODS.mRNA expression levels of ATM, DNA‐PKcs, and Ku80 were measured in tumor and adjacent normal tissues from 140 patients with NSCLC by using quantitative real‐time polymerase chain reaction analysis. Then, a Cox proportional hazards regression model and Kaplan‐Meier plots were used to evaluate the association between the tumor:normal (T/N) expression ratios of the 3 genes and the overall survival rate and duration in patients with NSCLC.RESULTS.mRNA expression of ATM and DNA‐PKcs, but not of Ku80, was significantly higher in tumor tissues than in adjacent normal tissues (P = .003 and P < .001, respectively). The high T/N expression ratios of ATM and DNA‐PKcs were associated significantly with a 1.82‐fold increased risk of death (95% confidence interval, 1.05–2.70) and a 2.13‐fold increased risk of death (95% confidence interval, 1.21–3.76), respectively. However, no significant association with risk was observed for Ku80. Kaplan‐Meier analyses revealed that patients with high T/N expression ratios of ATM or DNA‐PKcs had notably shorter median survival than patients with low ratios.CONCLUSIONS.The current findings suggested that the T/N expression ratios of ATM and DNA‐PKcs may be useful for identifying NSCLC patients with a poor prognosis who may benefit from more aggressive therapy. Cancer 2008. ©2008 American Cancer Society.

This study investigated the ability of MnCl2 as a cellular MRI contrast agent to determine the in vitro viability of human embryonic stem cells (hESC) and human bone marrow stromal cells (hBMSC). Basic MRI parameters including T1 and T2 values of MnCl2‐labeled hESC and hBMSC were measured and viability signal of manganese (Mn2+)‐labeled cells was validated. Furthermore, the biological activity of Ca2+‐channels was modulated utilizing both Ca2+‐channel agonist and antagonist to evaluate concomitant signal changes. Metabolic effects of MnCl2‐labeling were also assessed using assays for cell viability, proliferation, and apoptosis. Finally, in vivo Mn2+‐guided MRI of the transplanted hESC was successfully achieved and validated by bioluminescence imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.